I've been chasing this problem for one year now, read thru many of the previous threads, got alot of good info to try on my setup. I've definitly made the jeep stop better, but its still pretty bad. After dumping $400 in lines and a brake kit last week I'm kinda getting fed up.

Current Setup:
94 ZJ with HPD44 Ford Twin Piston Calipers, Rear D60 w/ 3/4ton Chevy Front Single Piston Calipers, No Prop Valve, Stock ZJ Disc/Disc Master Cylinder and Booster.

I started out with the stock componets on the ZJ with the HPD44 Twin brakes and drums rear. Low pedal, but would stop on the street. Took it out wheeling and I could not hold at all on a downhill in 2wd or 4wd low. Ditched the Stock MC for a Durango MC. Better street performance, still the same offroad performance. Then I decided on switching to Disc Calipers on the rear and the durango MC. Worst it ever was, pretty much no brakes. So I switched back to the ZJ MC and it stops pretty good on the street, but still lacking in 4wd downhill. Found a few more posts to remove the prop valve and it should lock up the rear brakes. So I ditched the Prop Valve and ran straight lines from the ZJ MC to the calipers, no better and the rear brakes dont lock up. Stuck a small 1/2" spacer on the end of the MC to the Booster Rod and it brought the pedal up and it felt decent.

After wheeling this weekend with the current setup. Level flat ground in 4wd low was livable. Down hills or roll off bigger rocks it would not hold when it needed to. Also once the booster pressure built up, about a mile into the day, it locked the brakes down, pedal high and very hard. Cut my spacer down to1/4" and it was fine the rest of the day.

What I dont understand after this weekend of watching some buggies, without boosters, running the same caliper setups I have on just Master Cylinder, How do they have no issues stopping and locking up brakes?

What should be my next step onto my brake system? I cant keep throwing hundards into my brakes and only get marginally better.

Thanks for your time.
Rick

Doing somemore research, I beleive my issues are in my single booster. Most of the posts/threads deal with dual boosters.

Anyone have some experince with this issue?

Rick

Doing somemore research, I beleive my issues are in my single booster. Most of the posts/threads deal with dual boosters.

Anyone have some experince with this issue?

Rick

I have the same setup Front and rear Ford 60's with Chevy 3/4 disk's on the rear. I replaced my booster with a dual from a 98 XJ and I have no problems at all. My pedal was low with the single booster, but the dual resolved that. I still have the stock MC and proportioning valve in and I can stop 42's on any hill in any condition. Check out vetteboys MC thread, he is using a Durango MC and I belive has no issues.

Thanks! I beleive I'm going to hit the junkyard this weekend and see what I can come up with.

Rick

pretty sure Vetteboy has the Dodge 2500 MC. I am using it too with the dual piston calipers and my pedal is mushy. Downhill wont stop but everywhere else works ok. :shaking: I've messed with the adjuster rod and if its adjusted out any more it just drags. Vetteboy also has a manual so I wonder if it works fine with the manual, cuz it would stop fine if I had a clutch to push in, but not with an auto and an Atlas 5.0 pushing along...

Did you get all the air out of the lines?

I'm way pass the did you get the air out of the lines. Its a componet issue.

Rick

just dont count that out though.

i had the same problems and thought the same thing. the answer could be easier than you think.


I'm way pass the did you get the air out of the lines. Its a componet issue.

Rick

100% confident the air is out. If it was air trapped somewhere when the booster build up pressure, the brake pedal would be spongey. It was rock solid.

Rick

i had a lot of braking issues with my 89 cherokee. Specs, stock front axal and a ford 8.8 in the rear. I went to the junk yard a picked up a duel diaphram booster and master cylinder off of a 01 grand cherokee with disk brakes. its a direct fit, with the exception of messen with the brake switch. i also turned up my idle to increase vacuume for the booster. that seemed to do the trick for me. Hope this helps.

ramsport59 did u fix ur problem cuz i have an 89 cherokee with a hp44 and 9'' and it has the same problem how did u fix ur problem and how well is it workin